Multi-omics provide evidence for an anti-inflammatory immune signature and metabolic alterations in patients with Long COVID Syndrome; an exploratory study (preprint)

Despite the increasing prevalence of patients with Long Covid Syndrome (LCS), to date the pathophysiology of the disease is still unclear, and therefore diagnosis and therapy are a complex effort without any standardization. To address these issues, we performed a broad exploratory screening study applying state-of-the-art post-genomic profiling methods to blood plasma derived from three groups: 1) healthy individuals vaccinated against SARS-CoV-2 without exposure to the full virus, 2) asymptomatic fully recovered patients at least three months after SARS-CoV-2 infection, 3) symptomatic patients at least 3 months after a SARS-CoV-2 infection, here designated as Long Covid Syndrome (LCS) patients. Multiplex cytokine profiling indicated slightly elevated cytokine levels in recovered individuals in contrast to LCS patients, who displayed lowest levels of cytokines. Label-free proteome profiling corroborated an anti-inflammatory status in LCS characterized by low acute phase protein levels and a uniform down-regulation of macrophage-derived secreted proteins, a pattern also characteristic for chronic fatigue syndrome (CFS). Along those lines, eicosanoid and docosanoid analysis revealed high levels of omega-3 fatty acids and a prevalence of anti-inflammatory oxylipins in LCS patients compared to the other study groups. Targeted metabolic profiling indicated low amino acid and triglyceride levels and deregulated acylcarnithines, characteristic for CFS and indicating mitochondrial stress in LCS patients. The anti-inflammatory osmolytes taurine and hypaphorine were significantly up-regulated in LCS patients. In summary, here we present evidence for a specific anti-inflammatory and highly characteristic metabolic signature in LCS which could serve for future diagnostic purposes and help to establish rational therapeutic interventions in these patients.

Preclinical establishment of a divalent vaccine against SARS-CoV-2 (preprint)

First-generation vaccines against SARS-CoV-2 have been administered to more than 60% of the population in developed countries. However, the monovalent vaccines currently available in Europe do not confer adequate and durable immune protection. To satisfy the need for a novel vaccine, we engineered a divalent gene construct consisting of the receptor binding domain (RBD, 300-685 aa) of the spike protein and the immunodominant region of the nucleocapsid (100-300 aa). This fusion protein was cloned into a pET-30a plasmid and expressed either in Escherichia coli or in a recombinant baculovirus in insect cells. Following purification via its His-tag, the fusion protein was mixed with adjuvant, and administered to mice in a prime-booster-mode. Upon testing for IgG antibody response against nucleocapsid and RBD, a titer of 10-4 - 10-5 was demonstrated 14 days after the first booster injection in 72% of the animals, which could be increased to 100% by a second booster. Notably, comparable IgG responses were detected against the delta, gamma and omicron variants of the RBD region. Durability testing revealed the presence of IgG beyond 90 days. In addition, granzyme A and perforin mRNA expression (cytolytic effector cell molecules) was increased in peripheral blood cytotoxic lymphocytes. Ex vivo stimulation of T-cells by nucleocapsid and RBD peptides showed antigen-specific upregulation of CD44 in vaccinated mice among their CD4+ and CD8+ T-cells. No side-effect was documented in the central nervous system, be it either endothelial inflammation or neuronal damage. Cumulatively, the combined induction of B-cell and T-cell response by a bivalent protein-based vaccine directed against two structural SARS-CoV-2 proteins represents a proof-of-principle approach alternative to existing mRNA vaccination strategies, which could confer long-lasting immunity against all known viral strains.